AUTOMOTIVE & MOTORSPORT FEATURE Meeting demanding market requirements using HIL TESTING TECHNOLOGY
Nicholas Keel, group manager at NI, discusses how HIL testing can reduce test time and broaden embedded software test coverage by simulating the world around an ECU
T
he automotive competitive landscape and customer expectations associated
with modern automobiles has escalated dramatically in recent years. Vehicle usability and functionality is no longer compared to previous generations of vehicles, but to consumer electronics such as cell phones and tablets. This has led to a dramatic rise in embedded software complexity on today’s cars and trucks, and this is clearly apparent in the body control modules (BCMs) in these vehicles. Mechanical components are combined or replaced with electrical and software based systems which provide higher levels of functionality. One technique that is commonly used to efficiently verify embedded software is hardware-in-the-loop (HIL) testing. HIL testing reduces physical testing time and broadens embedded software test coverage by simulating the world around an engine control unit (ECU) using a real-time test system with models and test scripts. It can cover a much wider range of scenarios than would otherwise be possible or practical, and tests can often be performed for a fraction of the cost of physical tests. Test engineers are able to perform
testing earlier in development and easily repeat tests for a variety of conditions to produce higher quality ECUs in less time than would otherwise be possible. For example, a BCM can be tested for a variety of user scenarios regardless of whether there are actually doors, windows or even a car frame available.
HIL TESTING FOR BCMS HIL testing for BCMs on modern automobiles represents unique challenges not found in vehicles of years past. Gone are the days of power windows serving as a differentiator between entry level automobiles and luxury saloons. Today’s vehicle has advanced sensors
that monitor tyre pressure, radar sensors, keyless entry and remote start capability, high definition touch screen displays and integrated wireless connectivity for Bluetooth, HD radio and cellular networks. All of these features must be thoroughly tested for reliability and usability and the tools required to perform these tests require functionality that has typically been reserved for testing cell phones and computer chips. The types of signals that must be generated and measured for BCM software testing extends beyond analogue and high speed digital found in traditional HIL systems. For example, remote entry systems require wireless communication from sensors to the controller and, in order to properly test the BCM, an HIL system must be able to generate the RF bands required to simulate the sensors and key fob. Passive entry passive start (PEPS) systems demand extremely high speed I/O communication while the pairing process between the PEPS module and key fob is fast and time sensitive. A very powerful technology that is critical in a flexible HIL test system is an open Field Programmable Gate Array (FPGA). FPGAs enable engineers to pre- program custom functionality by using reconfigurable hardware logic. This technology, coupled with a high speed digitiser, allows design engineers to precisely measure signals and perform analysis, including signal demodulating, recording start bid, header and data length and signal amplitude, which allows for accurate measurement of PEPS system performance. Another reason that FPGAs are
commonly utilised in BCM HIL testing is because they can perform custom inline
processing of signals with very low latency. A common requirement when testing BCMs is to analyse the quality of high speed digital PWM signals coming out of the controller, which is where using an FPGA to easily measure digital values such as duty cycle, pulse width and frequency can be extremely valuable. However, the FPGA also enables users to measure and process analogue properties of the signal such as max, min and RMS voltage values. The FPGA performs the processing and simply passes the processed data to the CPU for recording and monitoring. FPGAs are also reconfigurable, which allows users to change signal counts, processing types and processing requirements without needing to purchase new hardware.
THE NI PLATFORM FOR BODY CONTROL HIL Embedded software testing for BCMs requires techniques not often found in traditional HIL systems. BCMs blend the line between electronics that go into automobiles and that of consumer electronics. HIL systems used to test them must be able to accommodate these technologies which include RF acquisition and generation as well as custom high speed digital protocols. For this reason, NI’s platform is suitable for testing BCM software. NI is a tools provider for automotive embedded software development and consumer electronics test. Subaru use NI platforms to test their latest hybrid vehicles.
NI’s platform is
suitable for testing BCM software
NI
www.ni.com INSTRUMENTATION | FEBRUARY 2017 23
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